Fuel system diagnostics
Circuit Description
The fuel pump is located in the fuel tank and is mounted on the fuel sensor assembly. The fuel pump remains on while the engine is being started or running or the ECM is receiving control pulses from the crankshaft position sensor. If no control pulses are present, the ECM will shut off the fuel pump two seconds after the ignition is turned on or two seconds after the engine is stopped. The fuel pump supplies fuel to the fuel rail and to the fuel injectors, the fuel pump assembly maintains the pressure in the fuel system in the range from 401 to 418 kPa (58 to 61 psi inch). Excess fuel is returned to the fuel tank.
Attention! The fuel system is under pressure. Depressurize the fuel supply system before disconnecting fuel lines to prevent fuel spillage and burns.
Attention! Do not pinch or kink nylon fuel lines to avoid fuel leakage and related fires and injury.
Relieving pressure in the fuel supply system
1. Remove fuel cap.
2. Remove the fuel pump fuse EF16 from the engine fuse box.
3. Start the engine and turn it off.
4. Crank the engine for another 10 seconds.
Fuel system diagnostics
| Step | Operation | Values | Yes | No |
| 1 |
Fuel pressure within the set value, but not stable?
|
401~418 kPa (58~61 psi inch)
|
Go to operation 2
|
Go to operation 9
|
| 2 |
Check fuel lines for leaks.
Fault found?
|
-
|
Go to operation 3
|
Go to operation 4
|
| 3 |
Fuel pressure within the set value, but not stable?
|
401~418 kPa (58~61 psi inch)
|
System OK
|
-
|
| 4 |
Fault found?
|
-
|
Go to operation 5
|
Go to operation 6
|
| 5 |
Fuel pressure within the set value, but not stable?
|
401~418 kPa (58~61 psi inch)
|
System OK
|
-
|
| 6 |
Fuel pressure within the set value, but not stable?
|
401~418 kPa (58~61 psi inch)
|
System OK
|
-
|
| 7 |
Fault found?
|
-
|
Jump to operation 8
|
-
|
| 8 |
Fuel pressure within the set value, but not stable?
|
401~418 kPa (58~61 psi inch)
|
System OK
|
-
|
| 9 |
Is the fuel pressure below the set value and is it stable?
|
401~418 kPa (58~61 psi inch)
|
Go to operation 6
|
Jump to operation 10
|
| 10 |
Check fuel lines for leaks.
Fault found?
|
-
|
Go to operation 3
|
Go to operation 11
|
| 11 |
Fault found?
|
-
|
Go to operation 5
|
Go to operation 12
|
| 12 |
Fault found?
|
-
|
Jump to operation 8
|
Go to operation 6
|
Checking the fuel pump relay circuit; Checking the fuel pump relay circuit; Checking the relay circuit of the electric fuel pump
Circuit Description
With the ignition on, the ECM sends a signal to the battery to activate the fuel pump relay and operate the fuel pump in the fuel tank. The fuel pump is running while the engine is cranking or running and the ECM is receiving ignition control pulses.
If no control pulses are present, the ECM will shut off the fuel pump within 2 seconds after the ignition is turned on.
Diagnostic Information
An intermittent problem can be caused by a loose connection, frayed insulation, or a broken wire under the insulation.
Description of the test
The sequence corresponds to the steps indicated in the diagnostic table.
3. This operation tests the ground signal supplied by the ECM to control the fuel pump relay.
7. By checking the wiring in steps 2 - 6, you can detect a malfunction of the fuel pump relay.
9. After determining the absence of a ground signal from the ECM to the fuel pump relay, it can be assumed that the fault is in the ECM or in the wiring between the ECM and the fuel pump relay.
Checking the fuel pump relay circuit; Checking the fuel pump relay circuit; Checking the relay circuit of the electric fuel pump
| Step | Operation | Values | Yes | No |
| 1 |
Does the fuel pump run for the set time?
|
2 sec.
|
System OK
|
Go to operation 2
|
| 2 |
Turn on the ignition. Does the control lamp light up?
|
-
|
Go to operation 3
|
Jump to operation 8
|
| 3 |
Is the control lamp on?
|
2 sec.
|
Go to operation 4
|
Go to operation 9
|
| 4 |
Is the control lamp on?
|
-
|
Go to operation 5
|
Go to operation 11
|
| 5 |
Test the wire between terminal 87 of the fuel pump relay connector and terminal 4 of the fuel pump connector for an open circuit or short to ground.
Fault found?
|
-
|
Go to operation 6
|
Jump to Operation 7
|
| 6 |
Does the fuel pump run for the set time?
|
2 sec.
|
System OK
|
-
|
| 7 |
Does the fuel pump run for the set time?
|
2 sec.
|
System OK
|
-
|
| 8 |
Test for an open circuit between the fuel pump relay connector terminal 30 and the battery.
Fault found?
|
-
|
Jump to operation 13
|
-
|
| 9 |
Test the wire between the fuel pump relay connector terminal 85 and the ECM connector J1 terminal 51 for an open circuit.
Problem found?
|
-
|
Jump to operation 10
|
Go to operation 12
|
| 10 |
Does the fuel pump run for the set time?
|
2 sec.
|
System OK
|
-
|
| 11 |
Does the fuel pump run for the set time?
|
2 sec.
|
System OK
|
-
|
| 12 |
Does the fuel pump run for the set time?
|
2 sec.
|
System OK
|
-
|
| 13 |
Does the fuel pump run for the set time?
|
2 sec.
|
System OK
|
-
|
Checking the main relay circuit
Circuit Description
When the ignition is turned on or the key is turned to the START position, the main relay is energized. The main relay then energizes fuses Ef12 and Ef15 on the fuse box in the engine compartment.
Diagnostic Information
- An intermittent problem can be caused by a loose connection, frayed insulation, or a broken wire under the insulation.
- A faulty main relay will render the vehicle unable to start. There will be no voltage at the fuel injectors. Without voltage, the fuel injectors do not function.
Checking the main relay circuit
| Step | Operation | Values | Yes | No |
| 1 |
Does the test lamp light up on both terminals?
|
-
|
System OK
|
Go to operation 2
|
| 2 |
Check indicator lamp.
Is the indicator light on only one terminal?
|
-
|
Go to operation 9
|
Go to operation 3
|
| 3 |
Check indicator lamp.
Is the test lamp not lit on both terminals?
|
-
|
Go to operation 4
|
-
|
| 4 |
Is the fuse OK?
|
-
|
Go to operation 5
|
Jump to operation 10
|
| 5 |
Is the control lamp on?
|
-
|
Go to operation 6
|
Go to operation 11
|
| 6 |
Connect a test lamp between terminal 86 of the main relay connector and battery voltage.
Is the control lamp on?
|
-
|
Jump to Operation 7
|
Go to operation 12
|
| 7 |
Connect a test lamp between terminal 30 of the main relay connector and ground.
Is the control lamp on?
|
-
|
Jump to operation 8
|
Jump to operation 13
|
| 8 |
Check for an open circuit in the wire between terminal 87 of the main relay connector and the terminals on the fuse box in the engine compartment for fuses Ef12 and Ef15.
Fault found?
|
-
|
Go to operation 9
|
Go to operation 14
|
| 9 |
Repair the open circuit between terminal 87 of the main relay connector and the terminals on the fuse box in the engine compartment for fuses Ef12 and Ef15.
Has the renovation been completed?
|
-
|
System OK
|
-
|
| 10 |
Replace fuse Ef13 in engine compartment fuse box.
Has the renovation been completed?
|
-
|
System OK
|
-
|
| 11 |
Repair the open circuit between the main relay connector terminal 85 and the ignition switch.
Has the renovation been completed?
|
-
|
System OK
|
-
|
| 12 |
Repair the open circuit between the main relay connector terminal 86 and ground.
Has the renovation been completed?
|
-
|
System OK
|
-
|
| 13 |
Repair the open circuit between the main relay connector terminal 30 and the battery.
Has the renovation been completed?
|
-
|
System OK
|
-
|
| 14 |
Replace main relay.
Has the renovation been completed?
|
-
|
System OK
|
-
|
Checking Manifold Absolute Pressure
Circuit Description
Manifold absolute pressure sensor (IDA) measures the change in intake manifold pressure associated with changes in engine load and changes in engine speed. The MAP sensor converts these changes into output signals. Electronic engine management controller (ECM) supplies a 5 V control signal to the MAP sensor. As the intake manifold pressure changes, the MAP sensor output also changes. Low output level (high vacuum) 1 - 2 V takes place at idle. High output level (low vacuum) 4.0 - 4.8 V occurs at wide open throttle. The MAP sensor is used under certain conditions to measure barometric pressure. This allows the ECM to correct for changes in altitude. The ECM uses the MAP sensor to supply fuel and change ignition timing.
Description of the test
The sequence corresponds to the steps indicated in the diagnostic table.
2. Impact 34 kPa (10 inches Hg) vacuum to the MAP sensor should cause a change in signal level. Subtract the second signal level value from the first. The voltage value must be greater than 1.5 V. When a vacuum is applied to the MAP sensor, the signal level must change constantly. A slow change in signal level indicates a malfunction of the MAP sensor.
3. Detach the MAP sensor from the bracket and rotate the MAP sensor. Changes in the output signal greater than 0.1 V indicate a faulty connector or contact.
Checking Manifold Absolute Pressure
| Step | Operation | Values | Yes | No |
| 1 |
Is the difference between the two signal levels less than the set value?
|
0.4 V
|
Go to operation 2
|
Go to operation 5
|
| 2 |
Is the difference in signal levels greater than the set value?
|
1.5V
|
System OK
|
Go to operation 3
|
| 3 |
Check the MAP sensor connector terminals.
Fault found?
|
-
|
Go to operation 4
|
Go to operation 5
|
| 4 |
Repair the MAP sensor connector if necessary.
Has the renovation been completed?
|
-
|
System OK
|
-
|
| 5 |
Replace MAP sensor.
Has the renovation been completed?
|
-
|
System OK
|
-
|
Checking the ignition system
Circuit Description
The electronic ignition system uses a two-spark ignition method with a reference spark. In this electronic ignition system, the crankshaft position sensor is mounted on the oil pump near the splined wheel that is part of the crankshaft pulley. The crankshaft position sensor sends control pulses to the ECM. The ECM turns on the electronic ignition coil. When the ECM energizes the EI system coil, both connected spark plugs spark at the same time. One cylinder is on the compression stroke while the other cylinder is on the exhaust stroke, saving the energy needed to create a spark in the spark plug in the cylinder that is on the exhaust stroke.
The remaining high voltage is used to spark the spark plug in the cylinder on the compression stroke. Since the crankshaft position sensor is in a stationary position, adjustment of the ignition timing is not possible and is not necessary.
Description of the test
The sequence corresponds to the steps indicated in the diagnostic table.
2. It is important to check for spark on all cylinders in order to isolate the problem at the input or output signals of the electronic ignition system coil.
5. When checking the output signals for the presence of the ignition timing signal, it is recommended to use an oscilloscope to observe the change in the signals. When measuring these output signals with a voltmeter, intermittent faults may occur that are not detected by the voltmeter.
6. If the ECM ignition timing inputs to the EI system ignition coil are normal, then the cause of the problem is in the EI system ignition coil.
11. If the crankshaft position sensor inputs to the ECM are normal and there is no problem with the wiring, then the problem is in the ECM.
24. This step, together with step 25, checks the battery voltage and ground connection of the electronic ignition coil.
Checking the ignition system
Attention! To prevent electric shock when working with ignition wires while the engine is running, use insulated pliers.
| Step | Operation | Values | Yes | No |
| 1 |
Has the renovation been completed?
|
-
|
System OK
|
Go to operation 2
|
| 2 |
Check for spark at all ignition wires when cranking the engine with the starter.
Is there spark at all ignition wires?
|
-
|
System OK
|
Go to operation 3
|
| 3 |
Is there spark at all ignition wires?
|
30,000 ohm
|
System OK
|
Go to operation 4
|
| 4 |
Is there a spark on at least one ignition wire, but not all of the ignition wires?
|
-
|
Go to operation 5
|
Go to operation 12
|
| 5 |
Does the voltage fluctuate within the specified value?
|
0.2-2.0V
|
Go to operation 6
|
Jump to Operation 7
|
| 6 |
While cranking the crankshaft, measure the signal level at terminal 1 of the electronic ignition coil connector.
Does the voltage fluctuate within the specified value?
|
0.2-2.0V
|
Jump to operation 10
|
Jump to operation 8
|
| 7 |
Test for an open circuit in the wire from the EI system ignition coil connector terminal 3 to the ECM connector J2 terminal 35.
Fault found?
|
-
|
Go to operation 9
|
Go to operation 11
|
| 8 |
Check for an open in the wire between the EI system ignition coil connector terminal 1 and the ECM connector J2 terminal 40.
Fault found?
|
-
|
Go to operation 9
|
Go to operation 11
|
| 9 |
Is there spark at all ignition wires?
|
-
|
System OK
|
-
|
| 10 |
Is there spark at all ignition wires?
|
-
|
System OK
|
-
|
| 11 |
Is there spark at all ignition wires?
|
-
|
System OK
|
-
|
| 12 |
Is the resistance within the specified value?
|
400-600 ohm
|
Jump to operation 13
|
Jump to operation 28
|
| 13 |
Has the renovation been completed?
|
-
|
Go to operation 14
|
Jump to operation 28
|
| 14 |
Is the voltage within the specified value?
|
1.3-1.5V (2.4-2.7V) *
|
Jump to operation 20
|
Jump to operation 15
|
| 15 |
Measure the signal level between the crankshaft position sensor connector terminal 1 and ground.
Is the voltage within the specified value?
|
1.3-1.5V (2.4-2.7V) *
|
Go to operation 17
|
Jump to operation 16
|
| 16 |
Check for an open or short in the wire between the crankshaft position sensor connector terminal 1 and the ECM connector J2 terminal 14.
Fault found?
|
- |
Go to operation 18
|
Go to operation 11
|
| 17 |
Test for an open circuit in the wire between the crankshaft position sensor connector terminal 3 and ground.
Fault found?
|
-
|
Jump to operation 19
|
Go to operation 11
|
| 18 |
Repair the wire between the crankshaft position sensor connector terminal 1 and the ECM connector J2 terminal 14.
Has the renovation been completed?
|
-
|
System OK
|
-
|
| 19 |
Repair the wire between the crankshaft position sensor connector terminal 3 and ground.
Has the renovation been completed?
|
-
|
System OK
|
-
|
| 20 |
Is the voltage within the specified value?
|
1.3-1.5V (2.4-2.7V) *
|
Jump to Operation 24
|
Jump to Operation 21
|
| 21 |
Measure the signal level between the crankshaft position sensor connector terminal 2 and ground.
Is the voltage within the specified value?
|
1.3-1.5V (2.4-2.7V) *
|
Go to operation 17
|
Go to operation 22
|
| 22 |
Check for an open or short in the wire between the crankshaft position sensor connector terminal 2 and the ECM connector J2 terminal 15.
Fault found?
|
-
|
Jump to operation 23
|
Go to operation 11
|
| 23 |
Repair the wire between the crankshaft position sensor connector terminal 2 and the ECM connector J2 terminal 15.
Has the renovation been completed?
|
-
|
System OK
|
-
|
| 24 |
Is the control lamp on?
|
-
|
Jump to operation 25
|
Go to operation 26
|
| 25 |
Connect a test lamp between the EI system ignition coil connector terminal 2 and the positive battery cable.
Is the control lamp on?
|
-
|
Go to operation 5
|
Go to step 27
|
| 26 |
Check for an open or short in the wire between the EI system ignition coil connector terminal 2 and the ignition switch.
Fault found?
|
-
|
Go to operation 29
|
-
|
| 27 |
Repair the wire between the EI system ignition coil connector terminal 3 and ground.
Has the renovation been completed?
|
-
|
System OK
|
-
|
| 28 |
Has the renovation been completed?
|
-
|
System OK
|
-
|
| 29 |
Replace fuse F27 or repair open circuit between EI system ignition coil connector terminal 2 and ignition switch.
Has the renovation been completed?
|
-
|
System OK
|
-
|
Checking the cooling fan circuit
Circuit Description
The engine cooling fan circuit controls the main and auxiliary cooling fans. The cooling fans are controlled by the ECM based on engine coolant temperature sensor inputs (EATING) and air conditioning pressure sensor (ACP). The ECM is responsible for running the cooling fan at low speed by internal grounding terminal 43 of the ECM connector J1. This will activate the low speed cooling fan relay and the low speed main cooling fan. The ECM is responsible for running the high speed cooling fan by internally grounding the ECM connector J1 terminal 24. This will energize the high speed cooling fan relay and cause the fan to run at high speed because the cooling fans are now connected in parallel.
Diagnostic Information
- If the owner of the vehicle complains of an overheating problem, then it is necessary to determine whether the malfunction is related to the actual overheating of the engine or the overheating is only displayed on the coolant temperature indicator. If the engine overheats and the cooling fans are on, the cooling system should be checked.
- If fuse Ef9 or Ef8 of the engine compartment fuse box blows immediately after installation, test the related circuit for a short to ground. If the fuses blow when the cooling fans should be turned on by the ECM, the cooling fan motor may be faulty.
- The ECM turns on the cooling fans at low speed when the coolant temperature reaches 97°C (207°F). The ECM turns off the cooling fans when the coolant temperature reaches 94°C (201°F).
- The ECM turns on the cooling fans at high speed when the coolant temperature reaches 101°C (214°F). The ECM changes the speed of the cooling fans from high to low when the coolant temperature reaches 98°C (208°F).
- The ECM turns the fans on slowly when the A/C system is on. The ECM switches the cooling fans from low to high speed when the A/C pressure on the high pressure side is 1859 kPa (269 psi inch), then switches them back to low speed at a pressure in the air conditioner on the high pressure side of 1449 kPa (210 psi).
- The cooling fan circuit can be quickly tested by disconnecting the ECM and connecting J1 terminal 43 to ground. This will turn on the cooling fan at low speed when the ignition is on. By connecting terminal 24 of connector J1 of the ECM to ground and turning on the ignition, you can turn on the high speed of the cooling fan.
Checking the cooling fan circuit
| Step | Operation | Values | Yes | No |
| 1 |
Perform a diagnostic system check.
Check done?
|
-
|
Go to operation 2
|
Go to item "Diagnostic system check".
|
| 2 |
Fuse (And) serviceable (out)?
|
-
|
Go to operation 3
|
Go to "Diagnostic Information"
|
| 3 |
Is the cooling fan running at low speed?
|
-
|
Go to operation 4
|
Jump to operation 8
|
| 4 |
The cooling fans must run at high speed when the coolant temperature reaches 101°C (214°F).
Are the cooling fans running at high speeds?
|
-
|
Go to operation 5
|
Jump to operation 19
|
| 5 |
Is the cooling fan running at low speed?
|
-
|
Jump to Operation 7
|
Go to operation 6
|
| 6 |
Has the renovation been completed?
|
-
|
System OK
|
-
|
| 7 |
Are the cooling fans running at high speeds?
|
-
|
System OK
|
-
|
| 8 |
Is the control lamp on?
|
-
|
Go to operation 9
|
Go to operation 12
|
| 9 |
Connect a test lamp between terminal 1 of the main cooling fan connector and the positive battery terminal.
Is the control lamp on?
|
-
|
Go to operation 11
|
Jump to operation 10
|
| 10 |
Repair the open circuit between the main cooling fan connector terminal 1 and ground.
Has the renovation been completed?
|
-
|
System OK
|
-
|
| 11 |
Check the terminals in the main cooling fan connector for damage and repair or replace the main cooling fan.
Has the renovation been completed?
|
-
|
System OK
|
-
|
| 12 |
Does the control lamp light up in both cases?
|
-
|
Go to operation 14
|
Jump to operation 13
|
| 13 |
Restore the power supply circuit.
Has the renovation been completed?
|
-
|
System OK
|
Go to operation 14
|
| 14 |
Is the cooling fan running at low speed?
|
-
|
Jump to operation 15
|
Jump to operation 16
|
| 15 |
Replace the ECM.
Is the replacement finished?
|
-
|
System OK
|
-
|
| 16 |
Is the resistance within the specified value?
|
0 ohm
|
Go to operation 18
|
Go to operation 17
|
| 17 |
Fix open circuit.
Has the renovation been completed?
|
-
|
System OK
|
-
|
| 18 |
Replace the low speed cooling fan relay.
Is the replacement finished?
|
-
|
System OK
|
-
|
| 19 |
Is the control lamp on?
|
-
|
Jump to operation 20
|
Jump to Operation 24
|
| 20 |
Connect a test lamp between the auxiliary cooling fan connector terminal 1 and the positive battery terminal.
Is the control lamp on?
|
-
|
Jump to Operation 21
|
Jump to operation 23
|
| 21 |
Replace auxiliary cooling fan.
Is the replacement finished?
|
-
|
System OK
|
Go to operation 22
|
| 22 |
Repair the open circuit between the following terminals:
Has the renovation been completed?
|
-
|
System OK
|
Go to operation 11
|
| 23 |
Repair the open circuit between the auxiliary cooling fan connector terminal 1 and ground.
Has the renovation been completed?
|
-
|
System OK
|
-
|
| 24 |
Does the control lamp light up in both cases?
|
-
|
Go to operation 26
|
Jump to operation 25
|
| 25 |
Repair an open circuit in the power supply circuit:
Has the renovation been completed?
|
-
|
System OK
|
Go to operation 26
|
| 26 |
Are the cooling fans running at high speeds?
|
-
|
Jump to operation 15
|
Go to operation 27
|
| 27 |
Is the resistance within the specified value?
|
0 ohm
|
Go to operation 29
|
Jump to operation 28
|
| 28 |
Repair the open circuit between specific circuit wires.
Has the renovation been completed?
|
-
|
System OK
|
-
|
| 29 |
Replace the high speed cooling fan relay.
Is the replacement finished?
|
-
|
System OK
|
Jump to operation 15
|
Diagnosis via diagnostic block
Circuit Description
Means of communication with the controller of the electronic engine management system (ECM) is a diagnostic block (DLC). It is located below the toolbar. The diagnostic terminal is used to connect the scan tool. Battery power and a ground point are provided to the scan tool through the diagnostic connector. The ECM can communicate with the scan tool by linking the serial data circuit to the diagnostic module.
Diagnostic Information
Verify that the correct application has been selected on the scan tool (model line, year of manufacture, etc.). If communication cannot be established, connect the tool to another vehicle to ensure that the scan tool or cables are not causing the problem.
An intermittent fault can be caused by a loose connection, frayed insulation, or a broken wire under the insulation.
Any circuit suspected of producing an intermittent fault should be carefully checked for the following:
- Removed terminals.
- Weak terminal contact.
- Locks malfunction.
- Deformed or damaged terminals.
- Weak connection of terminals with wires.
- Physical damage to wiring harnesses.
- Corrosion.
Description of the test
The numbers below indicate the operation numbers in the diagnostic table.
1. The diagnostic system check prompts the technician to perform basic checks and save the fault status and data to the scan tool. This creates an electronic copy of the data recorded when a fault occurs. The information is stored in the scanning tool for further processing.
5. Locate and repair short circuits that could cause a blown fuse if the lack of voltage in the circuit was due to the blown fuse.
10. The scanning tool or its cables may be faulty. See the Scan Tool Service Manual.
Diagnosis via diagnostic block
| Step | Operation | Values | Yes | No |
| 1 |
Perform a diagnostic system check.
Check done?
|
-
|
Go to operation 2
|
Go to item "Diagnostic system check".
|
| 2 |
Using a test lamp connected to ground, check terminal 16 of the power supply of the diagnostic block.
Is the control lamp on?
|
-
|
Go to operation 4
|
Go to operation 3
|
| 3 |
Repair the open circuit or short to ground in the power supply circuit of the diagnostic pad.
Has the renovation been completed?
|
-
|
Go to operation 4
|
-
|
| 4 |
Using a control lamp connected to the power supply, check terminals 4 and 5 of the ground of the diagnostic block.
Is the control lamp on?
|
-
|
Go to operation 6
|
Go to operation 5
|
| 5 |
Repair open circuit.
Has the renovation been completed?
|
-
|
Go to operation 6
|
-
|
| 6 |
Does the scan tool turn on?
|
-
|
Jump to operation 8
|
Jump to Operation 7
|
| 7 |
Check the diagnostic terminal and scan tool for faults and repair as needed.
Has the renovation been completed?
|
-
|
Jump to operation 8
|
-
|
| 8 |
Using a scan tool, request engine data from the ECM.
Does the scan tool display any data?
|
-
|
Go to operation 12
|
Go to operation 9
|
| 9 |
Install the scan tool on another vehicle and check its operation.
Is the scan tool working properly on another vehicle?
|
-
|
Go to operation 11
|
Jump to operation 10
|
| 10 |
The scan tool is defective.
See the Scan Tool Service Manual.
Has the renovation been completed?
|
-
|
Go to operation 12
|
-
|
| 11 |
Repair the communication circuit between the ECM and the diagnostic module.
Has the renovation been completed?
|
-
|
Go to operation 12
|
-
|
| 12 |
Does the engine start and continue to run?
|
-
|
Jump to operation 13
|
Go to operation 2
|
| 13 |
Are DTCs displayed that were not diagnosed?
|
-
|
Go to section "Applicable DTC Table"
|
System OK
|
Injector balance check
The fuel injector tester turns on for a certain time to deliver a measured amount of fuel to the intake manifold. This causes a fuel rail pressure drop that can be recorded and used for comparison with each fuel injector. All fuel injectors should show the same pressure drop.
Example of checking the balance of injectors
|
Cylinder
|
1
|
2
|
3
|
4
|
|
First value
|
296 kPa (43 psi)
|
296 kPa (43 psi)
|
296 kPa (43 psi)
|
296 kPa (43 psi)
|
|
Second meaning
|
131 kPa (19 psi)
|
117 kPa (17 psi)
|
124 kPa (18 psi)
|
145 kPa (21 psi)
|
|
A fall
|
165 kPa (24 psi)
|
179 kPa (26 psi)
|
172 kPa (25 psi)
|
151 kPa (22 psi)
|
|
Medium Range: 156~176kPa (22.5~25.5 psi inch)
|
nozzle is ok
|
Faulty injector - pressure drop too high
|
nozzle is ok
|
Faulty injector - pressure drop too low
|
Attention! The fuel system is under pressure. Depressurize the fuel supply system before disconnecting fuel lines to prevent fuel spillage and burns.
Attention! Do not pinch or kink nylon fuel lines. Defective fuel lines can cause fuel leakage, resulting in fire and injury.
Note: To prevent flooding the engine, do not check the balance of the injectors more than once (including retesting of faulty fuel injectors) on a stopped engine.
Examination
1. Turn on the ignition to raise the fuel pressure to the maximum level.
2. Allow the fuel pressure to stabilize and record this initial pressure value. Wait until the pressure gauge needle stops moving.
3. Follow the manufacturer's instructions for using the adapter harness. Run the fuel injector tester once and record the fuel pressure drop at the lowest point. Write down this second value. Subtract it from the first value to determine the fuel pressure drop.
4. Disconnect the fuel pump tester from the fuel injector.
5. After switching on the ignition, to once again obtain the maximum fuel pressure, connect the tester to the next fuel injector. Turn on the fuel injector tester and record the fuel pressure value. Repeat this procedure for all injectors.
6. Recheck fuel injectors with a pressure drop of more than 10 kPa (1,5 psi) average pressure drop.
7. Replace fuel injectors that fail the test.
8. If the pressure drop of all fuel injectors is within 10 kPa (1,5 psi) average value of the pressure drop, the injectors are working normally and replacement is not required.
9. Reconnect the fuel injector harnesses and run the symptom diagnosis chart.
10. The engine must be allowed to cool down for 10 minutes to avoid distortion due to fuel vaporization on a hot engine.
11. Connect the pressure gauge carefully to prevent spillage of fuel.
12. The fuel pump should run for about 2 seconds after the ignition is turned on.
13. Put the transparent tube on the pressure gauge vent valve into a suitable container.
14. Completely bleed the air from the pressure gauge and hoses.
15. The ignition must be OFF for at least 10 seconds to complete the ECM shutdown cycle.